Semiconductor devices and disk drive heads have developed to the point where they are sensitive to the slightest charge, even charges as low as 5 volts. This sensitivity is problematic because it is very difficult to create an environment that is isolated from all static electricity and other charges. To complicate matters, most static charges will radiate a field having a radius as large as two feet. As a result, a charge on a person's arm or torso can damage a device on which they are working. The problem is so severe that up to 35% of the devices are irreparably damaged in some manufacturing facilities.
In an effort to eliminate this problem, these types of devices are manufactured in clean rooms that are specially designed to minimize static electricity. The workers typically wear grounding straps to provide an electrically conductive path to dissipate static charges. The workers also wear special coveralls that are also grounded.
Some clean rooms where semiconductor devices and disk drive heads are manufactured have a grounded floor that will dissipate electrical charges. Many workers rely on this floor to provide a ground for both their body and their coveralls. In this type of environment, the workers wear a boot that has a conductive bottom. Any charge in the boot will be conducted to the grounded floor and dissipated. The problem is that many workers also wear shoes having rubber soles in their boots. As a result, the worker's body is insulated from the floor and is not grounded. Another problem is that the coverall legs are stuffed in the boot's cuff and there is only incidental contact between the coverall and the boot. This incidental contact does not provide a reliable electrical path having a low resistance. The coveralls thus are not adequately grounded and may retain a harmful static charge.
Therefore, there is a need for an improved boot configured to have a reliable electrical contact with the worker's body. There is also a need for a boot configured to have a reliable electrical contact with the worker's coveralls.